Optical phased-array are widely used in a number of different applications including Light Detection and Ranging (LIDAR) systems in which beams of electromagnetic radiation or light are steered and light reflected from objects scanned to detect and determine the range of objects detected by the LIDAR system. Typically, optical phased-arrays used in LIDAR systems require fast beam steering and large scan angles.
One type of spatial light modulators (SLM) used in optical phased-arrays in LIDAR systems is a mechanical SLM, such as a laser scanner that includes a spinning or moving mirror to steer the light beam. Unfortunately, these mechanical SLMs are rather bulky and the relatively large mass of the mirror limits the speed with which the light beams can be steered or scanned.
Another type of SLM suitable for use in optical phased-arrays is a digital micromirror device (DMD) based SLM in which several hundred if not thousands of microscopic mirrors arranged in an array are electrostatically pivoted or tilted in response to electronic signals. Although capable of providing much faster beam steering than the mechanical SLM, achieving large scan angles requires small DMD dimensions, approaching the wavelength of the radiation being scanned. This in turn makes it difficult to maintain the speed advantage of the DMD-based LIDAR system.
Accordingly, there is a need for a SLMs and a method for operating the same to provide fast beam steering and large scan angles for phased-array applications.